1. Field
The present application relates to low friction polymeric materials for surfaces of devices, particularly medical devices and non-medical devices.
2. Related Art
Various medical devices (such as catheters, guide wires and the like) employ hydrophilic coatings to reduce friction when maneuvering these devices through blood vessels. Typically, the hydrophilic coating is applied in a four step process. In the first step, the device is fabricated (such as by extruding or compression molding the device). In the second step, a primer coat of isocyanate or isocyanate/prepolymer is applied to the device. In the third step, the hydrophilic coating (typically containing polyvinyl pyrrolidone or polyethylene oxide) is applied to the primer coat. In the fourth step, the system is cured.
Hydrophilic polyurethane coatings have been used to decrease the surface friction on medical devices. U.S. Pat. Publ. No. 2007/0014945 discloses that a certain hydrophilic polyurethane (i.e., Tecogel, which was formerly manufactured by Thermedics and now by Lubrizol under the Tecophilic® brand) can be coated on a medical devices, such as intravascular guidewires, catheters, and stents using dip coating and spray coating means. U.S. Pat. Publ. No. 2010/0048758 discloses the use of a hydrophilic coating realized by dipping or spraying the device in a solution mixture of TG-500 (which is manufactured by Lubrizol, Wilmington, Mass. and sold under the Tecophilic® brand), 1-methyl-2-pyrrolidinone and Sancure® 1073C (manufactured by Lubrizol, Cleveland, Ohio), followed by drying at 130° C. for five minutes. The Tecophilic® brand of products are hydrophilic aliphatic polyether urethanes which absorb water ranging from 20 to 1000% of their dry weight at equilibrium. TG-500 is one of the Tecophilic® polyurethanes. Sancure® 1073 is an aliphatic polyurethane that is hydrophobic in nature. Polyethylene oxide has also been used to prevent thrombus formation on surfaces and there are a large number of publications to this effect.
U.S. Pat. No. 4,642,267 describes a low friction hydrophilic polymer for medical devices that employs a blend of thermoplastic polyurethane and poly (N-vinyl lactam).